1. Field of the Invention
The present invention relates to systems and methods of presenting information generated on a computer to a user, and in particular to a method and apparatus for modifying an existing personal computer to operate with multiple displays.
2. Description of the Related Art
Most currently available computers are capable of operating in a multitasking environment. This allows the user to have several applications (e.g. a word processor, spreadsheet, browser, and e-mail program) open at the same time. Such computers are also capable of displaying multiple windows (typically, one for each application) on a single display. However, although such multi-window interfaces, (such as those provided by the WINDOWS NT, and WINDOWS ""98 operating systems) are useful, they can require large, expensive displays.
At the same time, the cost of displays, particularly liquid crystal displays (LCDs), is decreasing. This makes it possible to implement multiple displays, rather than a single display presenting multiple windows mounted, for example, in a desktop space.
Attempts have been made at using single computers to drive multiple displays. For example, European Patent Disclosure EP 0 779 573 A1 discloses the construction of a new personal computer (PC) having a plurality of cathode ray tube (CRT) controllers sharing the same display memory connected to a control unit by a bus. Although this system permits the use of a single computer to drive multiple displays, it requires the user to purchase a new unique PC, and cannot be used to modify existing PCs to drive multiple displays. Essentially, the system in this disclosure requires replacement of the entire system to provide multiple display capability. Further, the foregoing system does not provide an easy mechanism to increase the number of displays, since it requires special software running on the control unit to route display information to the CRTs.
What is needed is a system and method that allows currently available personal computers to be easily modified to provide multiple display capability. The present invention satisfies that need.
To address the requirements described above, the present invention discloses a method and apparatus for adapting a single computer to drive at least two displays.
The present invention is embodied in an apparatus for adapting a single computer to drive at least two displays. The apparatus comprises a controller, coupled between a user input device and a computer, the controller for providing a control signal according to a user input; and a video switcher, for selectively providing a signal from the computer to one of at least two video displays in response to the control signal.
The present invention is also embodied in a method of presenting information on at least two displays communicatively coupled to a computer. The method comprises the steps of intercepting a user input to the computer, and directing a video output signal from the computer to one of at least two video displays according to the intercepted video input.
The foregoing allows the use of multiple displays with a single ordinary computer without the disadvantages described above. The foregoing invention also allows each application to occupy a display. Only one application is active at a time; the application the user is interacting with by keyboard or by a mouse. The display of the active application is animated, all the other displays show a frozen image (using a RAM frame buffer). Hence, one PC is used to feed xe2x80x9clive imagesxe2x80x9d to an active display, and frame buffers are used to show frozen images on the inactive displays.
For example, a user writing a paper may have a word processor, a spreadsheet, Web page, and a reference paper active, with each presented on its own separate display (four displays). When the user is writing with the word processor, the word processor display is active and the rest would be inactive. The inactive displays would show the spreadsheet, Web page, and reference paper. When the user moves the mouse to the reference paper, the word processor display becomes an inactive display, and the word processor freezes the image on the page they are working on. To the user, it is as if all of the applications are running simultaneously since the users interact with only one application at a time.
Unlike the prior art described above, the present invention receives video from a conventional unmodified PC, taking advantage of the commodity market of existing PCs and can use the user""s existing PC. Further, the present invention allows the user to freely upgrade their PC without rendering the multiple display capability as obsolete.
The present invention also uses the primary display (typically the one in front of the user) as the active display. The systems disclosed in the prior art change the brightness of the display to indicate which is the active display. This can be visually annoying, since the user will be viewing all displays, even the dimmed displays. This confusion is avoided by the present invention, since only primary display (typically the one in front of the user) is active, and any secondary displays show only frozen images.
The present invention also allows the user to add additional displays as required by simple modification or replacement of the custom box. Prior art solutions require a new custom PC to be purchased or accessories to be added inside the custom PC. Conversely, the present invention uses a custom box that is external and independent of the customer""s xe2x80x9coff the shelfxe2x80x9d PC. Several custom boxes, supporting a variety of display resolutions and capacities can be provided by the invention.
The present invention also does not require any changes to the PC software. The present invention intercepts keyboard and mouse actions and passes them through to the PC. By intercepting these controllers, the video from the PC can be routed to the auxiliary displays by user control, without requiring special action of the PC.
The present invention also allows the user to program a sequence of keyboard and mouse input and play it back in a repeating loop. This allows one PC to perform the function of many. For example, a stock broker can have six screens connected to one PC using the invention, each one showing the trading values of a particular stock. The invention would sequentially update each screen, providing the effect of having six computers.